Ore-roasting furnace.



PATENTED AUG. 15, 1905.

H-C. HOLTHOFF.

. ORB ROASTING FURNACE.

APPLIOATION FILED MAY 0. 1903. RENEWED JULY 14,1904.

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H. G. HOLTHOFF. ORB ROASTING FURNACE. u'rmonmn rmm mu 8. 1903. nnunwnn JULY 14.1904.

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mmziw. a GRIMAM co. mnoun'nm 'm v mama PATENTED AUG. 15, 1905.

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PATENTED AUG. 15, 1905.

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H. 0. HOLTHOPF." ORE ROASTING FURNACE. LPPLIOLTIOI IILED IAY 6. i963. RENEWED JULY 14, 1904.

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PATENTED'AUG. 15, 1905.

H. G. HOL'I'HOFF. ORE ROASTING FURNACE. rum-non FILED Mu 6:1903. RENEWED J LY 14.19%

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UNITED STATES PATENT OFFICE.

AND MINING MACHINERY COMPANY, OF CUDAHY, WISCONSIN, A COR- PORATION OFWNEW JERSEY.

ORE-ROASTING FURNACE.

Specification of Letters Patent.

Patented Aug. 15, 1905.

Application filed May 6, 1903.. Renewed July 14, 1904. Serial No. 216,488.

1'9 all whom, it may concern:

Be it known that 1, HENRY C. HOLTHOFF, a

citizen of the United States, residing at Miltion, reference being had to the accompanying drawings, formlng a part thereof.

This invention relates particularly to furnaces for treating sulfurous ores; and its main ob ect is to lmprove the construction and operation of furnaces of this class.

It consists in certain novel features of construction and in the peculiar arrangement and comblnatlons of component parts of the apparatus, as hereinafter particularly described,

and pointed out in the claims.

In the accompanying drawings like characters designate the same parts in the several figures.

Figure 1 is a central vertical section on the line A B, Fig. 2, of a furnace embodying my invention. Fig. 2 is a half plan view of the same and a horizontal section in planes approximately indicated by the lines C D and E F, Fig. 1. Fig. 3 is an enlarged plan view of two of the stationary stirrers. Fig. 4 isa side View of one of the stirrers and a section on the line G H, Fig. 3. Fig. 5 is an enlarged plan view of one of the roller-bearings which support the rotary hearth. Fig. 6 is a side view of the same. Fig. 7 is an enlarged side view; and Fig. 8, a section on the line I J. Fig. 7, of the sprocket-wheel for turning the rotary hearth. Fig. 9 is a section, on a smaller scale, on the line K L, Fig. 10, of the sprocket-wheel and of the associated rack and track. Fig. 10 is a partial side view of the same. Fig. 11 is an enlarged plan view of a part of the wind-box at the inner edge of the cooling-floor. Fig. 12 is a vertical section on the line M N, Fig. 11. Fig. 13 is an enlarged plan view of a part of the wind-box surrounding the combustion-chamber; and Fig. 1 1 is a vertical section on the line O P, Fig. 13.

My improved furnace comprises generally a centrally-located circular gas-generating 0r combustion chamber a, an annular roastingchamber having a rotary bottom or hearth a, surrounding the upper part of the combustion-chamber, and an annular cooling hearth or floor 172, located below the rotary hearth and surrounding the lower part of the combustion-chamber.

The top of the roasting-chamber is formed by a roof or arch 9*, which may be constructed of brick, and is supported at its inner edge on the wall of the circular combustion-chamber and at its outer edge on a brick wall 8, supported by a circular mantle g, resting on the tops of columns a.

The revolving hearth consists of a sheetmetal bottom or floor resting onradial beams j and covered with sand or cinders, as shown in Fig; 1. It is supported at its outer and inner edges by circular tracks 6 and e on rollerbearings b, which are carried on the outer side by the columns a and on the inner side by columns a or by the wall of the combustion-chamber a. The bottom of the revolving hearth is provided at its outer edge with an upturned metal rim or curb h, which projects upwardly outside of and in close proximity with a depending metal apron f, which is attached to the mantle g and, with said rim or curb, closes the space between the outer 'edge of the revolving hearth 2' and the outer wall .9 of the roasting-chamber. The track 0 is attached to the under side of the beams j at their outer ends, as shown in Fig. 9, and the track 6 is attached to the lower edge of a sheet-metal skirting depending from the inner edge of the rotary hearth 2', as shown in Fig. 1.

The roller-bearings b, by which the rotary hearth is supported, consist, asshown in Figs. 5 and 6, of conical rollers b, mounted in pairs in double boxes 6 which are pivotally supported by pins 6 on bases 6, whereby the weight carried by the rollers is equalized. The boxes 6 are made to hold oil, which is carried up by the rollers, lubricating their bearings and the tracks 6 and e. Horizontally-disposed rollers 6, one of which is shown in Fig. 1, are arranged at intervals around the combustion-chamber u, so as to bear against the outer side of the track 6, and thus prevent lateral displacement of the rotating hearth i, which is turned by asprocket-wheel c, engaging a circular rack (Z on the under side and near the outer edge of said hearth. The sprocket-wheel is preferably constructed, as shown in Figs. 7 and 8, with separate teeth 0, detachably secured in the hub 0 The rack is preferably constructed as shown in Figs. 9 and 10, and consists of steel rollers d, mounted on bolts d between the inner side of the circular track a and a channel-iron attached to the under side of the beams j concentric with said track.

The cooling floor or hearth m consists of sheet metal laid on radial beams, which are carried at their outer ends by the columns a and at their inner ends by the columns a. It is provided at its outer edge with an upturned rim or curb for confining the ore thereon. At its inner edge a circular wind box or trunka;

, (shown in detailin Figs. 11 and 12) serves the purpose of the upturned rim at its outer edge. This wind-box is provided in the upper side with a series of valve-regulated intake-openings. The suction-pipe w of a fanblower w, located, as shown in Fig. 1, below the cooling-floor, is connected with the windbox 00, and the discharge-pipe 10 of the blower is connected with a circular wind box or trunk y, (shown in detail in Figs. 13 and 14,) surrounding the lower part of the combustionchamber a. Leading from the wind-box y upwardly through the wall of the combustionchamber are pipes M, which open at their upper ends into the roasting-chamber adjacent to passages or openings u from the upper part of the combustion-chamber into the roast.- ing-chamber and provided at their lower ends with regulatingvalves. The products of combustion and sulfurous fumes from the ore are conducted off through pipes q, distributed at intervals around the furnace, and leading upwardly from the outer part of the roastingchamber into a larger pipe or pipes g, which connect on one side of the furnace with a chimney or stack. The pipes q are provided with valves The roasting-chamber is provided with stationary stirrers, each consisting, as shown in Figs. 3 and 4, of a tubular arm or parallel pipes 0, passing through the roof or arch '2' of said chamber and provided at the lower end with a blade or rabble 0 One of the pipes 0 of each stirrer-arm is connected at its upper end by a hose 0 and regulating-valve 0 with a water-supply pipe 0, while the other pipe has an elbow or bend overhanging a trough 0" for carrying off the water discharged from the stirrer. Each stirrer is adjustably supported above the roof or arch 1' between two parallel horizontal beams by a split collar 0", which is clamped to the pipes 0 of the stirrer-arm and is fitted to turn in a sleeve or bearing 0, mounted on said beams. Below this supporting-bearing each stirrer-arm is provided with a split collar 0 which is clamped thereon, and to this collar is bolted a circular tile 0, which is fitted to turn and move vertically in a tile pipe or sleeve 2, fixed in the roof or arch 9", and serves to support the stirrer below its upper bearing and to close the opening in said pipe or sleeve around the pipes o. It will thus be seen that the stirrers are capable of vertical and angular adjustment to maintain their proper relation to the rotary hearth as the blades or rabbles wear away and to set the blades or rabbles at any required angle to the line of movement of the hearth for moving the ore across it more or less rapidly. The stirrers with the blades or rabbles at their lower endsare held at any angle to which they may be adjusted by clamps 0 as shown in Fig. 3.

To horizontal bars k, suspended fi omzthe beams j of the rotary hearth, are attached blades or rabbles Z at an'angle to move'the ore gradually across the cooling-floor m from its inner toward its outer edge. The ore to be treated is fed from a hopper t by a screw conveyer t or other means into the outer part of the roasting-chamber on one side of the furnace and is discharged from the inner part of said chamber through pipes nupon the inner part of the cooling-floor m below. The ore is discharged from the cooling-floor at or near its outer edge on one side of the furnace through an opening or spout a.

The operation of the furnace hereinbefore described may be briefly explained as follows: A fire having been started in the combustionchamber a and supplied with coal or other fuel through a suitable feed-opening, combustion is maintained by a forced blast of air and steam introduced through a pipe or nozzle entering the bottom of the chamber. The gas generated by the combustion of the fuel is discharged through the radial openings or passages a at the top of the chamber into the roasting-chamber and directed radially across the rotary hearth 2'. As it issues from the passages a into the roasting-ehamber it is ignited and supplied with oxygen to maintain combustion and oxidize the sulfur in the. ore under treatment by the heated air forced by the blower w through the trunky and pipes 10 The burning gases, products of combustion, and sulfurousfumes given off by the ore under treatment are carried radially and outwardly across the rotating hearth and escape through the branch pipes q and pipe or pipes q into the chimney or smoke-stack. The ore to be treated is fed constantly from the hopper t by the conveyer 23 upon the outer part of the revolving hearth ?I and is gradually moved toward the center of the furnace by the inclined blades 0 of the stirrers in a direction transverse to the direction of movement of the hearth vi and opposed to the direction of travel of the burning gases and products of combustion. At or near the inner edge of the revolving hearth the hot ore from which the sulfur has been removed in its circuit on the rotating hearth around the furnace from the outer to the inner side-of the hearth is discharged through the pipes at on vetgo'os 3 the cooling-floor m near its inner edge. It is gradually moved outwardly on the floor m by the inclined blades or rabbles Z on the radial stirrer-arms. is, which travel with the rotary hearth afromwhichtheyaresuspended. Upon arriving at the outer edge of the cooling-floor the ore is discharged on one side of the furnace through the opening or spout o. In its passage around and outward over the floor m the ore is cooled by the air drawn radially inward over it by the blower w through the wind-box a). The air is thus heated in cooling the desulfurized ore in its passage over itand is then heated to a higher temperature by its passage upward through the pipes a in the heated wall of the combustion-chamber. The rate of progress of the ore across the rotating hearth z' and across the cooling-floor m, and hence the time during which the ore will be subjected to the outfiowing burning gases and heated products of combustion in the roasting-chamber and to the inflowing coolair current on the cooling-floor, may be regulated as desired by changing the inclination of the blades or rabbles 0 of the stationary stirrers and of the blades or rabbles Z of the rotating stirrers. Destruction of the stationary stirrers by the intense heat to which they are subjected in the roasting-chamber is prevented by the cooling water flowing through the tubular arms or pipes 0. When the hearth is covered with ore, it fills and seals the space between the rim h and the apron f, preventing ingress of air to the roasting-chamber. In itspassage with the rotary hearth around the furnace and gradually inward across the hearth the ore is stirred by the stationary rabbles and everypart of it is subjected to the heat of the fire and products of combustion radiating in all directions from the combustion-chamber, so that no raw ore can be discharged from the furnace. For the treatment of certain kinds of oressuch, for example, as contain a large percentage of sulfur-the fire in the combustionchamber may be discontinued after the furnace is started or altogether omitted, and the air necessary to maintain combustion may be supplied either through the pipes. a or through the combustion-chamber a and openings n, or through both. For certain kinds of work the floor 00 and trunks m and y, as well as the cooling-floor'm, maybe omitted, the pipes a or under certain conditions the combustion-chamber a and the openings 26 affording a sufficient draft and supply of air. Various changes in details of construction may be made without materially affecting the principle or mode of operation of the furnace and without departing from the intended scope of my invention. l claim 1. In an ore-roasting furnace the combination of a central gas-generating or combustion chamber, and a roasting-chamber having ing-cham ber having an annular floor or hearth I communicating on the inner side with the up: per part of said combustion-chamber through radially-disposed openings or passages distributed around it, an exit pipe or flue connected with the outer part of said roastingchamber by branches distributed around it, and means for gradually moving the ore across said floor or hearth, substantially as described.

4. In an ore-roasting furnace the combination of a central combustion-chamber, an annular roasting-chamber communicating therewith through openings which are distributed around it and having a rotary floor or hearth, means for'turning said floor or hearth and exit-pipes distributed around and communicating with the outer part of said roastingchamber, substantially as described.

5. In an ore-roasting furnace the combination of a central combustion-chamber, an annular roasting-chamber communicating on the inside with said combustion-chamber and having exit-openings distributed around the out side, and air-supply pipes or passages leading along the combustion-chamber and opening into the roasting-chamber adjacent to the openings from the combustion-chamber, substantially as described.

6. In an ore-roasting furnace .the combination of a central combustion-chamber, an ann ular roasting-chamber communicating therewith and having a rotary hearth, and stirrers having inclined rabbles arranged in series across said hearth, substantially as described.

7. In an ore-roasting furnace the combination of a central combustion-chamber, an annular roasting-chamber having a rotary floor or hearth, stationary stirrers having tubular arms passing through the roof of the roasting-chamber and provided at their lower ends with inclined blades or rabbles, which are arranged in series across said floor or hearth, and a water-supply pipe connected with the inlet-passages of the stirrer-arms above said roof, substantially as described.

8. In an ore-roasting furnace the combination of a combustion-chamber, a roastingchamber communicating therewith and having a rotary floor or hearth, a water-supply pipe, a waste-trough, and stirrers having tubular arms passing through the roof of the roasting-chamber and comprising inlet pipes or passages which have flexible connections with said supply-pipe and outlet pipes or passages which overhang said trough at their upper ends. substantially as described.

9. In an ore-roasting furnace the combination of a central combustion-chamber, a roasting-chamber communicating therewith and having a rotary annular floor or hearth surrounding said combustion-chamber, and stirrer-blades having arms passing through the roof of the roasting-chamber and capable of vertical and angular adjustment therein, substantially as described.

10. In an ore-roasting furnace the combination of a combustion-chamber, a roastingchamber communicating therewith and having a rotary floor or hearth, and a series of cylindrical openings passing vertically through the roof, a series of cylindrical supports arranged above said openings, stirrerblades attached to the lower ends of pipes which are provided with collars capable of turning in said openings and supports, a water-supply pipe having flexible connections with the inlet-pipes and a waste-trough arranged underneath the overhanging upper ends of the outlet-pipes of said stirrers, substantially as described.

11. In an ore-roasting furnace the combination of a central combustion-chamber, a roasting-chamber communicating therewith and having a rotary annular floor or hearth surrounding the combustion-chamber, an annular cooling floor or hearth surrounding said combustion-chamber below the roastinghearth, and means for discharging ore from the roasting-hearth upon the cooling-hearth, substantially as described.

12. In an ore-roasting furnace the combination of a combustion -chamber, a roastingchamber communicating therewith and having a rotary annular hearth surrounding the combustion-chamber,a stationary annular coolinghearth surrounding said com bustion-chamber below the roasting-hearth, stationary stirrers constructed and arranged to move the ore progressively across the roasting-hearth, and movable stirrers constructed and arranged to move the ore across the cooling-hearth, substantially as described.

13. In an ore-roasting furnace the combination of a combustion-chamber, a roastingchamber communicating therewith and having a rotary annular hearth surrounding the combustion-chamber, a stationary annular cooling-hearth surrounding the combustion-chamber below the roasting-hearth, means for feeding ore to one side of the roasting-hearth, conduits for discharging the ore from the other side of said hearth upon the coolinghearth, which has a discharge spout or opening at the opposite side, stationary stirrers constructed and arranged to move the ore across the roasting-hearth, and rotary stirrers constructed and arranged to move the ore in an opposite direction across the cooling-hearth, substantially as described.

14. In an ore-roasting furnace the combination of a central combustion-chamber, an annular roasting-chamber surrounding the same and communicating therewith, an annular cooling floor or hearth surrounding said combustion-chamber below the roasting-chamber, an annular wind-trunk having intake-openings distributed around the inner side of the cooling-floor, a blower connected on its suction side with said trunk and blast-pipes connected with the discharge side of the blower and opening into the roasting-chamber around its inner side, substantially as described.

15. In an ore-roasting furnace the combination of a combustion-chamber, an annular roasting-chamber communicating therewith, an annular cooling-floor surrounding said combustion-chamber below the roasting-chamber, an annular wind-trunk having intake-openings distributed around the inner side of said cooling-floor, air pipes or passages located in the wall of the combustion-chamber and opening into the roasting-chamber adjacent to the openings into the same from the combustion-chamber, and a blower arranged to draw air from .said trunk and discharge it into said pipes,

substantially as described.

16. In an ore-roasting furnace the combination of.a combustion-chamber, an annular roasting-chamber communicating therewith through openings which are distributed around it and having gas-outlet. connections or openings distributed around its outer side, an annular cooling-floor surrounding the combustion-chamber below the roasting-chamber, a wind-trunk having intake-openings distributed around the inner side of the coolingfioor, air pipes or passages located in the wall of the combustion-chamber and opening into the roasting-chamber around its inner side and a blower arranged to draw air from said trunk and discharge it into said pipes, substantially as described.

17 In an ore-roasting furnace the combination of a combustion -chamber, an annular roasting-chamber communicating therewith through openings which are distributed around its inner side and having valve-regulated outlet connections or openings distributed around its outer side, an annular coolingfloor below the roasting-chamber, a windtrunk having valve-regulated intake-openings distributed around the inner side of said floor, valve-controlled air pipes or passages arranged in the wall of the combustion-chamber and opening into the roasting-chamber around its inner side, and a blower arranged to draw air from said trunk and discharge it into said pipes, substantially as described.

18. In an ore-roastingfurnace the combinae tion of a combustion-chamber, an annular roasting-chamber communicating therewith openings distributed around the inner side of the cooling-floor, a wind-trunk around the combustion-chamber, pipes or passages leading upwardly from said trunk through the wall of the combustion-chamber and opening, into the roasting-chamber around its inner side and a blower arranged to draw air from the first trunk and discharge it into the second trunk, substantially as described.

19. In anore-roasting furnace the combination of a combustion-chamber, a roastingchamber communicating therewith and having gas-outlet openings distributed around its outer side and an annular floor or hearth, an annular cooling-floor below the roastingchamber, conduits arranged to discharge ore from the inner part of the roasting-chamber upon the inner part of the cooling-floor which has a discharge spout or opening on the outer side, means for feeding ore to the outer side of the roasting-hearth, means for gradually moving the ore inward across the roastinghearth, means for gradually moving the ore outward across the cooling-floor, and means for drawing air inward across the coolingfloor and discharging the same outward across the roasting-floor, substantially as described. 20. In an ore-roasting furnace the com bination of a roasting-chamber, a cooling-floor below the roasting-chamber, means for moving the ore gradually inward across the floor of the roasting-chamber and discharging the same upon the inner part of the cooling-floor, means for moving the ore gradually outward across the cooling-floor and discharging the same at its outer side, and means for drawing air inward across the cooling-floor and discharging the same outward across the floor of the roasting-chamber, substantially as described.

21. In an ore-roasting furnace, the combination of a roasting-chamber having a rotary floor or hearth and inlet and outlet openings, arranged centrally and at the outer side of said chamber, for the supply of ore and air to the furnace and for the discharge of ore and smoke and gases from the furnace, means for turning the floor or hearth and means for gradually moving the ore radially across the floor or hearth from the supply to the discharge opening therefor, the air-inlet and the smoke and gas outlet openings being oppositely arranged with relation to the ore inlet and discharge openings, and the air or gas openings at the outer side of said chamber being distributed around the furnace whereby the air and products of combustion are made to pass radially through said chamber in a course opposite to the movement of the ore across the floor or hearth, substantially as described.

22. In an ore-roasting furnace the combination of a combustion-chamber having a rotary floor or hearth, an air-supply passage or opening communicating with the central part and an exit opening or passage communicating with the outer part of said chamber, a source of heat also communicating with the central part of said chamber, means for turning said floor or hearth, and means for gradually moving the ore across said .floor or hearth, substantially as described.

In witness whereof 1 hereto afiix my signature in presence of two witnesses.

HENRY O. HOLTHOFF.

Witnesses:

MAUDE L. EMERY, (JI-IAs. L. Goss. 

